In conventional electric power steering electric motor apparatuses, an electric motor and a controlling unit are formed integrally, and are disposed so as to be coaxial to a shaft that extends from a gearbox that reduces rotational speed of the electric motor, the controlling unit being disposed between the gearbox and the electric motor, and a power supplying part of the electric motor and a connecting part of the controlling unit are connected to each other inside the housing or inside the case through an opening part that is disposed on the housing or the case or both.
In the above configuration, the connecting part, which extends out from the controlling unit, and the power supplying part, which extends out from the electric motor, are overlapped and joined by a screw (see Patent Literature 1, for example).